This invention relates to a safety device and more particularly concerns an electronic system which causes an alarm to sound prior to the electrical activation of unattended moving equipment.
It is well known in the oil production industry that many wells containing crude oil most efficiently produce when the pumping apparatus is operated intermittently. The cycle is regulated by a control timer which may be adjusted to run the pump for a designated time interval and then shut the pump off for another designated time interval. The timing device switches a relay which in turn switches the high voltage to the pump. Shutting the pump off allows underground oil to seep into the shaft of the well so that it may be pumped out during the next pumping interval. Since wells even in close proximity may have different geological characteristics, the pumping cycle may vary from one well to another.
Oil pumping rigs are by nature large apparatus having a pivotally reciprocating member with heavy counterweights and driving a vertically oriented piston. Like all other machinery, oil pumps are subject to normal wear and tear in the course of operation. Periodic maintainence and repairs are necessarily performed upon the pumps by oil field workers. The workers will often approach the pumping rig at a random point within the pumping cycle, not knowing when the pump will next begin operation. While such work is being performed upon the pump, it has been known for the pump to start-up without warning and thereby cause injury to workers. Due to the size and mass of the pump, a worker may be easily crushed to death if caught underneath the pivoting member. Even when a start-up time is anticipated, the workers may be caught by surprise and not have time to clear the area.
It is therefore an object of the present invention to provide an alarm system for warning workers to clear the area prior to operation of an oil pump.
It is another object of the present invention to provide a system of the aforesaid type which will delay the starting of an oil pump during the duration of the alarm.
It is yet another object of the present invention to provide a system of the aforesaid type which may be over-ridden to facilitate testing of the pump without delay.